I'm not even defending it at all, I am saying that his tax return wouldn't have the information that you guys seem to want.
You need the financials that accompany the tax return to get his networth. Financials are audited too. I hope he releases his tax returns but he has to be careful in the way he does release them.
I am thinking the thought process behind it without being simplistic which you are being (thinking that he has something to hide because he is not releasing it).
I would say that he will release it eventually and the media outlets will read it, take one part out of context and run the story of it for days and days about how Trump avoids taxes etc.
People will not read his actual tax return because it will be likely 300 pages and will go to news outlets looking for TL

R therefore any actual truth regarding the tax return will take yonks to catch up.
This is why media outlets want it released because Trump gives them ratings because he is outrageous and on the fringe. People like hearing good or bad about Trump. His name sells... simple.